1. Field of the Invention
The present invention relates to means for maintaining the sterility of a packaging line during start-up or web transfer, and more particularly, to means for providing a sterilized splice between an expiring web of sterile tubing and a new web of sterile tubing or between a sterilizing boot and a web of sterile tubing at start-up.
2. Prior Art
U.S. Pat. No. 4,021,283, May 3, 1977, discloses a method of making aseptic packaging. As disclosed in this patent a continuous, blown film tube of plastic material is formed under aseptic conditions, flattened, and thereafter provided with a series of regularly spaced transverse seals which extend from one edge of the flattened tube to a point short of the opposite edge to form a channel along that edge to receive a filling nozzle. By sterilizing the filling nozzle prior to its insertion in the web of tubing, and also sterilizing the product to be packaged, aseptic conditions are maintained within the bags, which are thereafter filled and sealed without being opened to the atmosphere. In the case of food products, for example, this provides a greatly increased shelf life.
U.S. Pat. application Ser. No. 886,921, filed Mar. 15, 1978, now U.S. Pat. No. 4,171,604, is directed to a method for maintaining the asepsis of a web of bags such as that shown in U.S. Pat. No. 4,021,283 during start-up and transfer from one web of bags to another. In accordance with the method disclosed in the above-noted application, a flexible boot is attached about the filling nozzle prior to commencement of the packaging operation and the nozzle is thoroughly sterilized by the introduction of steam or some other sterilizing agent into the boot. After the nozzle has been sterilized an absorbant pad is positioned between a surface of the boot and an opposing surface of the leading end of a web of packaging material to sterilize these opposing surfaces. The nozzle is provided with a special fitting which then allows the nozzle to pierce through the opposing surfaces of the boot and the leading end of the web of bags. This permits the nozzle to be introduced into the web of bags under aseptic conditions.
When the initial web of bags is expended a new web of bags is brought into the packaging machine in a similar manner. Thus, a pad of absorbant material containing a sterilizing medium such as hydrogen peroxide is interposed between the opposing surfaces of the trailing end of the expiring web of bags and the leading end of the new web of bags, and once again using the special attachment on the filling nozzle, a hole is punctured through the opposing surfaces of the two webs of bags, allowing the nozzle to pass under aseptic conditions from the old web into the new one.
While the system described above maintains the sterility of a web of bags as it is introduced into the filling line, it will be apparent that the individual fabrication and application of a pad of absorbant material each time a start-up or transfer is made and the use of a special piercing nozzle assembly can be both time consuming and expensive.